I will leave it to people more knowledgeable than me to answer your question but I have noticed the RPM runs a little higher on the '17 (about 1600) than my previous '11 (about 1400). Perhaps why some have said the mpg is down a bit.

 

Here are some comparison spec's between the 2010 to 2017 6.7 diesel engines.
6.7L Power Stroke Diesel Specs & Info

 

Pretty sure there is no SST on the '17 trucks. They did change the oiling or cooling passages, but the '17 turbo is a direct drop in for '15-'16 trucks with the correct gasket. '11-'14 trucks can run a '17 with all the supporting mods.

I want to say it was posted that after a certain point any '15-'16 truck that needs a new turbo will get the '17 turbo as a replacement.

 

After getting a 'too heavy' fifth wheel last year, I gave serious consideration to trading my '12 for a new '17, because the '17 had a huge towing rating increase for SRW; 28,700 GCWR and 20,600 G/neck tow. But, with a $75k truck with less than 40k miles, that's a big expense to eat. I dug into just why the new truck was rated to tow so much more with the same engine, trannie, suspension, srw, etc. Yes, the engine and trannie pump out more hp and torque, but the same results can be achieved by tuning, and deleting (if you want to go that route). I compared differential, brakes, shocks, tires, and all were the same on both trucks. And for those of us that replaced shocks with Bilsteins, added air bags, anti-sway bars, increased fluid capacity on trannie and diff, and increased tire size to carry 4100 instead of 3750, I don't get the added tow rating for the 17. And before I get lectured, I know that the GVWR/GCWR cannot be changed. But in my logical mind, I believe that my truck is equipped better than the '17 and can safely tow just as much. But, no, I would not want to attempt to tow a 20k trailer with mine, the 17, or any other srw truck. So, other than dropping some weight by using aluminum, I don't see the difference.